74 (Bulletin of the jNatural History Society. 
while straggling members of the group seem to indicate that 
they have but recently retreated from the southern hills. 
In contrast with these we have the following New England 
plants in the southwest of the province: 
Viburnum acerifolium, Lobelia cardinalis, 
V. dentalum, Potamogeton hybridus, 
V. Lentago, P. rufescens, 
Cephalanthus occidentalis, Cladium mariscoides, 
IsoCtes echinospora, var. Braunii. 
Some of these are scarce; others are very abundant in suit- 
able localities. Eone of them have yet been seen farther 
east, but all occur in Maine. While for want of information 
they cannot be traced back in an unbroken line, yet they 
seem like the advanced guard of a host of invading plants, 
slowly advancing, and, unless checked by some secular change 
of climate, destined to cover the greater part of New Bruns- 
wick before they reach their limit of growth. 
Though the evidence is not conclusive, and at best would 
not prove an interrupted amelioration of climate, still, it 
would seem, the present condition of our Acadian flora, to 
some extent, favors the opinion that our climate has, within 
comparatively recent times, been growing less severe, and the 
general tendency of plant migrations has been toward the 
north. 
